Without giving away too much, I'm going to declare an earlier suspicion from the start that's finally confirmed in this episode:

It looks like the story of Moon Angel will be a re-imagining of Arnval Mk2's in-game event. After all, weird occurrences like memory loss and sudden berserker fits seem to have more dimension from a Shinki whose origins are unknown compared to a store-bought one with unchecked development bugs.

Wow, just wow.......Awesome episode. That ending......To be continued! Now I need to get around to fully reviewing both episode 2 & 3 before ep 4 comes out.....

Spoiler time![spoilers]The owner of the Busou Shinki store - Ken - keeps making me think of the person I know haha. And Arnval, wow. Quite a happy one but and obeying Shinki, powerful at that too. Zelno appears to have allowed her Master's rude personality rub off on her, ah well. Love the insertion of the Battlemasters MK 2 music, effects, and stage - Ride On![/spoilers]

Awesome episode, and still bought through the Japanese PSN for those wondering .

Kaguya also said in one part that her weapons were custom-made by her master. So apparently, Tsubasa is a tuner as well. If ever his work was included in game, I wonder what his initials would be? +TB, +TS?